Expansible rotary drill bit



Oct. 6, 1953 A. w. KAMMERER 2,654,574

EXPANSIBLE ROTARY DRILL BI T Filed Jan. 9. 1950 2 Sheets-Sheet 1 iii 2.

' I N VEN TOR. ARCHER W [YA/14445252,

Oct. 6, 1953 A. w. KAMMERER 2,654,574

EXPANSIBLE ROTARY DRILL BIT Filed Jan. 9. 1950 2 Sheets-Sheet 2 I N V EN TOR. AQCHEQ WZHMMEREB,

' 1Q TOE/V5).

are disposed. These cutter supporting members are opposed to one another and have their upper ends mounted on pivot or hinge pins 23 extending across the body slot and suitably secured to the body, as by the use of welding material 2d. The cutter supporting legs 22 depend from their hinge pins 23 to a substantial extent. They each have a bearing supporting pin 25 at the lower end, on which a roller side cutter It! is rotatably mounted. Anti-friction roller and ball bearing elements 26, 21 are disposed between each bearing supporting pin 25 and cutter ill, to reduce the friction therebetween. The ball bearing elements 21 also serve to retain the cutter on the bearing supporting pin.

The balls 2'. may be inserted between each cutter l8 and its associated pin 25 through a passage 28 in the latter, which is closed by a suitable plug 29 welded, or otherwise suitably secured, to the The bearing supporting members 22 and their cutters iii are opposed to one another, and may occupy retracted positions substantially entirely within the confines of the main bit body H, or

they may be expanded outwardly of the body to h a larger effective diameter than the inside diameter of the casing string C through which the bit is moved, for the purpose of enlarging th well bore below the casing shoe. In expanding the cutters it, their supporting legs 22 are swung outwardly about the hinge pins 23 to a predetermined extent.

The device for expanding the cutters includes a lower tubular member 30, which actually forms part of the mandrel l2, and which is piloted withing a lower socket 3| in the Kelly !3. The kelly l3 and lower tubular member 36 are assembled together for joint longitudinal movement by a swivel connection 32, which enables the lower tubular member to move angularly with respect to the upper kelly. Such swivel connection may include ball bearing elements 33 mounted in a raceway 34 formed on the boss portion 35 of the lower member 30, the ball bearing elements also being rollable in an internal raceway 36 formed in the kelly itself. The balls may b inserted in place through a passage, 3? extending through the Kelly flange I8. After the required number of balls have been mounted in the raceways 3d, 35, they are held in assembled position by a plug 38 in the passageway 37, which is prevented from inadvertent outward movement from the passageway by engaging the main bit body ii.

The lower tubular member 3! depends from its boss portion 35 through a guide and thrust member 39, which rests upon a shoulder 46 formed on the body. This thrust member initially is disposed below the lower end of the kelly l3, so as to allow the kelly l3 and tubular member 38 to be moved downwardly, for the purpose of holding the cutters l6 and their supporting members 22 in an outward position, resisting inward movement of the cutters l8 from their outward position and, under some conditions, actually shifting the cutters to their outwardly expanded position. The lower end of the mandrel member 39 is slidable in a lower guide M integral with the body H, and forming a support for the mandrel to resist its lateral movement.

The mandrel also has a cup-shaped thrust head d2 intermediate the upper and lower guides 39, M which has a depending skirt '43 terminating abov a thrust block 44 slidable along the exterior of the mandrel member 30 below the skirt $3. The block is in the form of a cross in transverse &

section, its diametrically opposed ribs t5 being slidable in longitudinal grooves or guideways 45 in the body ll. Another pair of diametrically opposed ribs ll, at right angles to the other ribs i5, are in longitudinal alignment with the cutter supporting legs 22. Each rib til carries a pin 48 on which the upper end of an inclined thrust link 49 is pivoted, the lower end of each link carrying a pivot pin passing'through a supporting leg between the hinge pin 23 and cutter l8, and preferably nearer the latter.

It is to be noted that th block ribs ll are each received within a groove 5! in an associated link 49, and that the lower end of each link is also provided with a groove 52 slidably receiving a rib 53 formed on the inner portion of the leg 22. The sides 54 of the links themselves are slidable along and are guided by the walls of the body slot 2| (see Fig. 6).

The cutters H3 may be expanded outwardly upon downward movement of the kelly I3 and lower tubular member 3% with respect to the body I l, causing the lower end of the thrust skirt 43 to engage the block 34, shifting the latter downwardly and swinging the legs 22 outwardly about their hinge pins 23 through the agency of the thrust links 59. If desired, outward expansion of the cutters ill and their supporting legs 22 may be accomplished by means of a helical compression spring 55 disposed within the skirt t3 and bearing at its upper end upon the thrust block 44. It is evident that this spring 55 tends to urge the thrust block 44 downwardly and the legs 22 in an outward direction.

The cutters it may be locked in retracted position by a holding device to insure the downward passage of the bit through the casing C, and to enable the bit to be moved to any desired point in the well bore below the casing shoe D before the hole enlarging operation is commenced. This holding device may include a holding plate 56 having holes 5'! receiving'the lower ends of the ball retaining plugs 29. The plate 56 will prevent outward expansion of the cutters it until the plate is removed. As disclosed in the drawings, removal may be effected hydraulically. A central rod 58 is secured to the plate 56 and projects upwardly into the central passage 59 formed through the lower tubular member 82 A head 60 at the upper end of the rod 58 fits loosely within the passage 59, to enable fluid to pass upwardly through the tubular member passage 59 and the body passage 6i and into the drill pipe B. A ball 62 may also be disposed in the passage es, or may be dropped down the drill pipe B when the cutters are to be expanded, this ball having a diameter substantially equal to the diameter of the passage 59, so as to function as a piston and enable the fluid under pressure within the drill pipe B and drill bit A to force the central rod 58 downwardly and remove the holding plate 53 from the plug elements 29, whereupon the cutters l0 and their supporting members 22 can be shifted laterally outward.

The tool A is assembled at the well bore, with the parts occupying the position illustrated most clearly in Fig. 2, the holding plate 58 securing the cutters H) in retracted position, with the spring 55 (when a spring is used) under maximum compression. The tubular mandrel I2 is disposed upwardly with respect to the body II, as limited by engagement of the Kelly flange it? with the retainer ring E9. The bit is attached to the drill pipe B and is lowered in the well bore.

When the location in the bore hole below the casing shoe D has been reached at which the underrea-ming or "hole enlarging operation is to commence, the pumps at the top of the well bore are started and the fluid in the drill pipe B subjected to pressure. This pressure acts upon the ball 82 and forces both the ball and the central rod 58 out of the passage 59, which removes the holding plate 56 from the plug el-ements'2'9, and allows the entire holding device to be ejected from the bit, leaving the passage 59 free and allowing the circulating fluid to exit from the lower end of the passage til-onto thecutters 10, for the purpose of maintaining them in a clean condition and to wash the cuttings upwardly tothe top of the well bore.

After the holding device has been removed,

the spring .55 can expand. This expanding action urges the thrust block 44 downwardly land, through the thrust links 49, swings the "cutter supporting legs 22 about their *hingepins 23 in an outward direction, forcing the'cutters against the Wall of the formation. The drillpipe Bend the rotary drill bit A are then rotated at the proper speed, the cutters digging into the wall of the formation and forming a shoulder Etherein, the spring expanding and forcingthe cutter supporting members 22 and cutters-l0 outwardly to an extent limited by engagement of the thrust block 4% with the upper end of the'lower'body guide ll (see Fig. 3). When the thrust block has reached this lowermost position relative to the-body, the cutters it have been'expanded'outwardly to the maximum extent.

With the formation shoulder "E'having :been formed, the drill pipe B may be lowered which will shift the :mandrel [-2 downwardly relative to :the body H, to the extent limited byengagement of the Kelly is withlthe upper guide and thrust member 39. The drilling weight is then transmitted through this :latter member to the body 1!], and from the body and 'hingepins23 to the cutter supporting legs .22 and roller cutters [0. With the impositioniof the :proper drillingweight, the drill pipe and tooLca-mbe rotated :to roll :the cutters around the formation .sshoulder IE and cause it to dig into-the latter.

Following release of the holding :;device from the cutter supporting members 22, the -spring 55 expands and :moves the :slide blockiM :awaytrom the lower endof the thrustskirtflfi. Accordingly, after the formation shoulder Eihaskbeenformed and thedriving .kelly 313 has been shifted down- Jwa-rdly of the body i 'into 1 engagementylith :the guid 39, the "cup-shaped :thrust :memberAzE and its skirt 43 are shifted towardtheslide 1310014544, 'which has :theeffect of virecompressing the spring ;-55..and..causing it tO increase its outward thrust .on the :cutter supporting ,1egs122,:therebyrtending to maintain the cuttersupportinglegssZZ inztheil maximum expanded positions. {Tl-162133111138 .rareiso proportioned :and arranged that, :aiter iilowering of .the .kelly 13 into .;engagement with the guide ;washer:39, the lowerlend ofithe skirt this slightly above the upper end sofnthe thrust block.;-'M :(aEig. '3). "In this :manner, none :of the drilling-weight is transmitted through the lower tubular "member 1.38 -;to .the thrust ."block .1144; -..all-;of1it passing from thezkelly l3 throughthe ithrust memberitil directly to the body \H. However, the slight space that .then. exists'ibetween the-thrust block A4 (and the lower :endof vithe skirt limits the inward .movement .of the .cutters 1.0 from :their fully outward position. :In the 1: event that the ;formation tends :to SQ11ZB the I, cutters inwardly, :they :can .only :move airom their :tfully :ex-panded position to .a .comparatively-minorextent, -limited 6. by engagement of the thrust {block 144 with the lower .end of theskirt .43, as the thrust block is shifted upwardly.

After the well bore has been enlarged to the proper extent, or the cutters have become worn, the :tool may be withdrawn from the well bore simply :by raising the string .-,of drill pipe B. ,At the commencement of this elevating movement, the ke'lly :13 and tubular member :30 are lifted within the bitbody H, to the extent determined by .engagementof the Kelly shoulder It with the retainer ring 19. This action decreases the compression of the spring 55 and allows the cutters 10.130 be returned .to retracted position @more readilyiuponmovementof the cutter legsZZ with the casing shoe D. The shoe engages the cutter legs 122 and shifts them inwardly of the bit .body, the legs riding the .wall of the-wellcasing .10 ,duringe'levation of thedevice within the latter.

The cutter expanding spring 55 need not be used inthe .event that the body II .can be sup.- ported against downward movement. As .disclosed in Fig. .1, a pilot :bit gF may be threaded into a box 10 formed at the-lowerend of thetool body. The device .can be lowered through the well casing, with thelatch mechanism 56, 58in place, and .with .the spring .55 omitted. "When :the pilot bit Fengages the bottom of the well ibore, the pumps may be started and the 'holding :device ejected hydraulically from the plug elements ,29 and from the bit itself. Since the pilot bit 'F is resting on the'bottom of .the hole, :the body I I :attachedtheretogcannot be moved down,- wardly. This enables the drill pipe B to .be low.- ered while the drill pipeandthe bitare being rotated, which forces the'lower end. of the thrust skirted? against thethrustblcck 54, shiftingthe ilatter in. a downward directioniandaforcing the :legs :22 and cutters 1:5! outwardly through the agency of the links $29. In this manner, the shoulder E is produced inthe formation, the-out- -.ward extent of the shoulder being determined by engagement of the thrust block a l with-the lower body guide i l, or by engagement of the 'lowerend of the Kelly [3 with the upper guide .member 39.

The :holeenlarging operation-may; then'prcceed in the'same manner. as described above, the pilot bits]? drilling the small diameter central portion of the hole and the reaming cutters it enlarging :the' hole to. the desired diameter.

'f Inasmuchas the lower end pf the1skirtg i3is engaging the upper end of the thrust block 44, thecutters it are prevented from moving inewardly from theirdesired maximum position to even.a slight extent.

Byproviding the swivel coru ectionv 32 between the vkelly i3 and lower tubular member 33, the :drilling torque is nottransmitted tothe latter, and, therefore, cannot have any tendency for turning the thrust =block.. ll and the links A9 "attached to it. This action might tend .to bend the-pins's23 and other parts of the device. ,All :of the drillingtorque is transmittedfrom ethe .ikellyittlto the body H of'thet-ool. Inaddition, the drilling weight is preferably transmitted =directly from the :kelly elstothe :body ll ofthe tool by causing the lower end of the kelly to engage the upper washer-39, and without the thrust skirt .133 engagin the thrust block d4, -.which wouldztendrtoiurge the. cutters it further outward beyond theirdesired reamingd-iameter.

-rIt :is 11303136 .noted that the link connection 39 ':between g-the thrust block 14 and each cutter :leg

22 is close to the cutter itself. As a result, comparatively long cutter supporting legs 22 can be used, to obtain comparatively large outward expansion of the cutters Ill, and still maintain adequate strength in the cutter supporting parts 22. The link connections 49 form intermediate braces between the cutters H3 and their hinge pins 23, which not only tends to withstand the bending, moment imposed on the cutter supporting legs 22 by the drilling weight, but also resists inward movement of the cutters It as a result of the reactive thrust of the formation thereon. The actual lever or moment arm of the cutter force against the formation is held to a relatively low value, inasmuch as the links 49 are connected to the cutter supporting members 22 close to the cutters themselves. These links 49 not only act as braces in preventing deflection of the long cutter supporting legs 22, but they also interconnect the legs through the thrust block 44, offerin assurance that the torque transmitted through the cutter supporting legs is substantially evenly divided between such legs and preventing inordinately high loads from being imposed on any one arm.

The thrust block ill also resists inward movement of the cutter supporting legs 22 from their outward expanded position, inasmuch as any inward thrust is transmitted through the links as to the block, and from the block ribs 45 to the main body i! of the bit. As noted above, the ribs 35 have a sliding fit in the grooves d5 of the body and contact the body walls of the grooves. In addition to resisting such inward thrust, the block ill and the links 59 serve to transmit the rotary motion and torque from the body ii to the cutter supporting legs 22. It is to be noted that the ribs it of the blocks make a sliding fit in the inner link grooves 53 and that the links themselves make a sliding fit with the walls of the body slot 2 i. Moreover, the leg ribs 53 make a sliding lit in the outer link grooves 52. By virtue of this arrangement, the turning eiiort imparted to the body ii by the kelly 53 is transmitted directly from the body to the links 49. and from the links to the supporting legs 22. Part of this turning effort is transmitted from the side walls of the body grooves 36 to the thrust block id and from the thrust block ribs ll to the thrust links 29, from where it passes to the supporting legs 22.

From the arrangement of parts, it is apparent that the major portion of the torque is transted directly from the body to the thrust links re, and from the thrust links to the supporting legs 22 at points that are relatively close to the cutters it. Very little of the torque is transmitted to the supporting legs 22 at or near their upper hinge pin ends. The link connecting pins 38, 56 also transmit very little, if any, of the drillin torque, in View of the manner in which the thrust links ie straddle and closely embrace the thrust block ribs ti and the ribs 53 projecting inwardly from the cutter supporting legs 22. Since the links are connected to the legs near the cutters it, relatively long legs can be used to obtain a large expansion of the cutters without much bending effort being imposed on the legs.

It is, accordingly, apparent that an expansible rotary drill bit has been provided, which has a very large range of expansion, enabling it to enlarge well bores to diameters that are exceedingly greater than the inside diameter of the casing string through which the tool must pass.

Despite such extreme range of expansion, the tool possesses adequate strength and sturdiness.

The inventor claims:

1. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body; a mandrel connectible directly to a drill string and slidably splined to said body; cutters mounted on said supporting members; means movable longitudinally relative to said mandrel and connected to said supporting members for expanding said supporting members and cutters outwardly; means for moving said movable means longitudinally relative to said mandrel; an abutment on said mandrel adjacent said longitudinally movable means; said mandrel being movable longitudinally with respect to said body to locate said abutment in a position to engage said longitudinally movable means to limit retraction of said longitudinally movable means, whereby the cutters are held in their outwardly expanded position.

2. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body; a mandrel connectible directly to a drill string and slidably splined to said body; cutters mounted on said supporting members; a member slidable along said mandrel and longitudinally movable with respect to said body; links interconnecting said slidable member and supporting members to expand said cutters outwardly upon longitudinal movement of said slidable member with respect to said body; means for moving said slidable member longitudinally with respect to said body to expand said cutters outwardly; an abutment on said mandrel adjacent said slidable member; said mandrel being movable longitudinally with respect to said body to locate said abutment in a position to engage said slidable member to limit retraction of said slidable member, whereby said cutters are held in their outwardly expanded position.

3. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body; a mandrel having an abutment thereon and connectible directly to a drill string and slidably splined to said body; cutters mounted on said supporting members; a thrust member slidable along said mandrel; links interconnecting said thrust member and supporting members; and spring means engaging said thrust member and said abutment for shifting said thrust member along said mandrel, in order to expand said supporting members and cutters laterally outward.

4. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body; a mandrel connectible directly to a drill string and slidably splined to said body; cutters mounted on said supporting members; a thrust member slidable along said mandrel and movable longitudinally of said body; links interconnecting said thrust member and supporting members; means on said mandrel engageable with said thrust member to move said thrust member longitudinally of said body; and means on said body engageable with said thrust member to stop movement of said thrust member with respect to said body.

5. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body; a mandrel connectible directly to a drill string and slidably splined to said body; cutters mounted on said supporting members; a thrust member slidable along said mandrel; links interconnecting said thrust member and supporting members to swing: said supporting members and cutters laterally outward upon longitudinal movement of said thrust member in one direction along said body; means for moving said thrust member longitudinally along said body in said one direction; and means on said mandrel engageable with said thrust member tolimit return movement of said thrust member in the opposite longitudinal direction-.-

6. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body and depending from their pivotal axes; a mandrel connectible directly to a drill string and slidably splined to said body; cutters mounted on the lower ends of said supporting members; a thrust member slidable along said mandrel; links interconnecting said thrust member and supporing members, said links being connected to said supporting members between their pivotal axes and the cutters; and means on said mandrel for moving said thrust member downwardly relative to said body to swing said supporting members and cutters outwardly.

7. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body and depending from their pivotal axes; a mandrel connectible directly to a drill string and slidably splined to said body; cutters mounted on the lower ends or said supporting members; a thrust member slidable along said mandrel; links interconnecting said thrust member and supporting members, said links being connected to said supporting members between their pivotal axes and the cutters; means on said mandrel for moving said thrust member downwardly relative to said body to swing said supporting members and cutters outwardly; and means on said body engageable with said mandrel to limit downward movement of said mandrel with respect to said body.

8. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body and depending from their pivotal axes; a mandrel having an abutment and connectible directly to a drill string and slidably splined to said body; cutters mounted on the lower ends of said supporting members; a thrust member slidable along said mandrel; links interconnecting said thrust member and supporting members, said links being connected to said supporting members between their pivotal axes and the cutters; and a spring engaging said abut ment and said thrust member for moving said thrust member downward relative to said body to swing said supporting members and cutters outwardly.

9. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body and depending from their pivotal axes; a mandrel connectible directly to a drill string and slidably splined to said body; cutters mounted on the lower ends of said supporting members; a thrust member slidable along said mandrel; links interconnecting said thrust member and supporting members, said links being connected to said supporting members between their pivotal axes and the cutters; means for moving said thrust member downwardly along said body to swing said supporting members and cutters laterally outward; and an inverted cupshaped member secured to said mandrel and engageable with said thrust member to prevent upward movement of said thrust member rela tive to said body.

10. In a rotary drill bit: a main body; a plurality of, supporting members pivotally mounted on said body and depending from their pivotal axes; amandrel connectible to a drill string and slidably splined; to said body; cutters, mounted on. the. lower ends of said supporting members; a. thrust member slidable along said mandrel; links interconnecting said thrust member and supporting members, said links being connected to said supporting members between their pivotal axes and the cutters; an inverted cup-shaped member secured to said mandrel and engageable with said thrust member to prevent upward movement of said thrust member relative to said body; and a spring within said cup-shaped member engaging said thrust member for shifting said thrust member downwardly relative to said body to swing said supporting members and cutters outwardly.

11. In a rotary drill bit: a main body; a supporting member pivotally mounted on said body; a mandrel connectible directly to a drill string and slidably splined to said body; a cutter mounted on said supporting member; means movable longitudinally relative to said mandrel and connected to said supporting member for expanding said supporting member and cutter outwardly; means for moving said movable means longitudinally relative to said mandrel; an abutment on said mandrel adjacent said longitudinally movable means; said mandrel being movable longitudinally with respect to said body to locate said abutment in a position to engage said longitudinally movable means to limit retraction of said longitudinally movable means, whereby said cutter is held in its outwardly expanded position.

12. In a rotary drill bit: a main body; a supporting member pivotally mounted on said body; a mandrel having an abutment thereon and connectible directly to a drill string and slidably splined to said body; a cutter mounted on said supporting member; a thrust member slidable along said mandrel; a link interconnecting said thrust member and supporting member; and means for shifting said thrust member along said mandrel, in order to expand said supporting member and cutter laterally outward, said means including spring instrumentalities engaging said thrust member.

13. In a rotary drill bit: a main body; a plurality of supporting members pivotally mounted on said body; a mandrel connectible directly to a drill string and slidably splined to said body; cutters mounted on said supporting members; a thrust member slidable along said mandrel; links interconnecting said thrust member and supporting members to swing said supporting members and cutters laterally outward upon longitudinal movement of said thrust member in one direction along said body; means on said mandrel engageable with said thrust member to shift said thrust member in said one direction along said body; and means on said mandrel engageable with said thrust member to limit return movement of said thrust member in the opposite longitudinal direction.

1%. In a rotary drill bit: a main body; a supporting member pivotally mounted on said body; a mandrel connectible directly to a drill string and slidably splined to said body; a cutter mounted on said supporting member; means movable downwardly along said body and operative-1y connected to said supporting member for expanding said supportin member and cutter outwardly; an abutment on said mandrel above said downwardly movable means; means engageable with said movable means for moving said movable means downwardly of said body; said mandrel being movable downwardly along said body to locate said abutment in a position to engage said downwardly movable means to limit retraction of said downwardly movable means, whereby the cutter is held in its outwardly expanded position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Douglass Mar. 27, 1883 Smith Mar. 21, 1911 Rudkin Apr. 30, 1924 Terrell Oct. 15, 1929 Cramer Dec. 3, 1929 Santiago Aug. 15, 1939 Rawlinson, Sr Sept. 13, 1949 

